Improvement in acoustic telephones



J. R. HOLGOMB. Acoustic Telephone No. 205,864. Patented July 9,1878.

WA Mweses. V W- if? UNITED STATES PATENT OEEIoE.

JAMES R. HOLCOMB, OF YORK, OHIO.

IMPROVEMENT IN ACOUSTIC TELEPHONES.

Specification forming part of Letters Patent No. 205,864, dated July9,1878, application filed June 19, 1678.

To all whom it may concern.-

Be it known that I, JAMES R. HoLcoMB, of York, in the county of Medinaand State of Ohio, have invented a certain new and Improved AcousticTelephone; and I do hereby declare that the following is a full, clear,and complete description thereof, reference being had to theaccompanying drawings, making a part of the same.

The nature of this improvement in acoustic telephones relates to thearrangement of a diaphragm within a tube and funnel-shaped month-piece,so constructed as to form a recess upon one side of the diaphragm and achamber upon the other. The improvement also relates to the combinationof the tube with the peculiarly-formed mouth-piece, and diaphragminterposed between them, the object of which is to cause the full volumeand force of the voice to act directly upon the diaphragm withoutdeflecting; and by means of the mouth-piece the force of the voice isconcentrated upon the central part of the diaphragm in contact with theline. Hence there is more energy produced, and the communications aretaken over a longer conducting-wire with more distinctness than in theordinary telephones of this class.

For a more full description, reference will be had to the followingspecifications and annexed drawings, in which Figure 1 is a view of thetelephone. Fi is a transverse vertical section, and Fig. view of outsideend and chamber.

Like letters of reference refer to like parts in the several views. V

The mouthpiece A is of wood or other suitable material, to one end ofwhich is fitted the tube B, as seen at 0, Figs. 1 and 2, holding thediaphragm D in place, which is first placed on the inner end of themouthpiece, and then drawn over the side, as seen at E, so that thelapped part E of the diaphragm is between the tube and mouth-piece, asshown in Fig. 2. By this means the three sections of the instrument arefirmly secured together, presenting a neat and finished appearance.

The mouth-piece A is made with an outside flaring opening at F, andcontracts at the inner end G, which is in open relation with the recessand central part of the diaphragm. Between the diaphragm and mouthpieceis a recess, H, and a chamber, I, on the opposite side formed by thetube B. The line J is connected with the diaphragm by means of thebutton K in the recess opposite the opening G. The diaphragm may be ofparchment or its equivalent.

Having described the construction and arrangement of the instrument, Iwill now set forth the principle of its operation.

In using it, the flaring mouth-piece is applied to the lips, which givessufficient space for the free utterance of the message to be sent, andis concentrated in its passage through the opening of the mouth-pieceand impinged upon the button and central part of the diaphragm, and bymeans of the recess H deflection is prevented. as all reverberation isconfined within the inclosed recess or chamber H. Hence all the force ofthe voice acts directly upon the central part of the diaphragm, where itis the most sensitive to acoustic influence, and, as there is but littleor no reflection in the recess, the volume of sound is expended upon thediaphragm, causing immediate, strong, and distinct vibrations, which aretaken over the line with more energ t and precision than would be thecase if acoustic action is allowed to extend over the entire face of thediaphragm and permitted to be reflected therefrom.

The message over the line is always weak and indistinct in proportion tothe acoustic volume lost by reflection from the diaphragm and itsinsufficient vibration from the force expended upon it; and by means ofthe chamber I the resonance and vibrations of the diaphragm is to acert-ain'ext'ent protected from atmospheric action and otherinfiuences,which cause the volume of sound through the mouthpiece to beclear and distinct in the instrument, and each reverberation istransmitted over a longer line and more distinctly than by the ordinarytelephone made with the diaphragm at the end of the tube. The deranginginflu

